Terahertz gas discharge: current progress and possible applications

Abstract

Plasma created in focused beams of electromagnetic waves in the terahertz frequency range is a fairly new object in gas discharge physics. The specified range, located between the microwave and infrared regions of the spectrum of electromagnetic waves, is currently being actively developed. However, until recently, the study of discharge phenomena in it was practically inaccessible. Recent advances in its development are associated primarily with the creation of powerful sources of terahertz radiation—gyrotrons and free electron lasers. This article presents an overview of the latest results of studies of a gaseous terahertz discharge: gas breakdown, discharge propagation, features of the discharge glow, and prospects for a gaseous terahertz discharge as a point source of UV radiation.

Point-like plasma-limited high-temperature terahertz laser discharge

“…The terahertz laser discharge is attractive mostly because the optimal gas pressure for maximum absorption of radiation lies in a technically convenient range of several atmospheres. This is in contrast to short-wave lasers, where pressures of tens and hundreds of atmospheres are required [1], and millimeter radiation sources, where pressure is significantly lower than the atmospheric one [2].…”

“…Note that the NovoFEL discharge differs from the above gyrotron discharges in the time-averaged thermodynamic quasi-equilibrium of plasma particles, which are of approximately the same average temperature. It should also be noted that the terahertz discharge at NovoFEL, due to the higher radiation frequency, has a much higher plasma density compared to gyrotron discharges [2], and to create an EVUV gyrotron source it is necessary to increase the radiation frequency and plasma density. Although the NovoFEL power, as in gyrotron facilities, mainly goes to the electron component, its timeaveraged value is not large enough for the energy 'lift-off' of the electron component from the ion one at high plasma density.…”

Reduction of polarization deviation effects in terahertz splitter

“…Because of its special position in the electromagnetic spectrum, terahertz wave has many excellent properties and attracts the attention of scientists and researchers all over the world [1][2][3]. Relevant researches show that the unique characteristics of terahertz wave have a wide application prospect in deep space exploration [4,5], nondestructive testing [6,7], medical`diagnosis [8,9], environmental science [10,11], biochemistry [12,13] and basic physics [14][15][16].…”

Разложение Углекислого Газа В Разряде, Поддерживаемом Непрерывным Сфокусированным Субтерагецевым Излучением При Атмосферном Давлении

“…Возможность проведения подобных исследований появилась сравнительно недавно благодаря созданию мощных гиротронов субтерагерцевого диапазона, работающих в непрерывном и импульсном режимах [4]. В субмиллиметровом диапазоне использование систем квазиоптической фокусировки электромагнитного излучения позволяет локализовать область поддержания разряда до размеров порядка длины волны и тем самым обеспечить высокий удельный энерговклад в плазму [5]. Электронная плотность в таких разрядах близка к критической для данной частоты греющего поля, а температурные характеристики плазмы имеют существенно неравновесное распределение [6].…”